The ability of users to access programs and share data over local area networks (referred to as “LANs”) has become a necessity for most working environments. To improve efficiency and ease of use, certain enhancements may be added to a LAN such as remote wireless access. By providing remote wireless access, a wireless LAN (WLAN) is formed.
As described in U.S. Pat. No. 5,987,062 issued to Netwave Technologies, Inc., now owned by Nortel Networks Limited, one type of WLAN employs dedicated stations, which are referred to as access points (APs). Therein, each AP is a relay station that receives data packets from a mobile unit (MU) such as a notebook-type computer with a suitable adapter card as described in U.S. Pat. No. 5,987,062. Thereafter, the AP transmits the data packets received from the mobile unit to the fixed backbone network. Of course, the AP also receives data packets from the fixed backbone network for transmission to one or more mobile units.
Before data transmission can occur between the fixed backbone network and an MU via an AP, the AP must first authenticate the respective MU. The authentication is accomplished by the MU transmitting a request for authentication message to the AP, and the AP sending back a successful authentication message to the MU. Once the MU has been authenticated, the MU has to associate itself with the AP. The association is accomplished by the MU transmitting a request for association message to the AP, and the AP sending back a successful association message to the MU. The authentication and association transmission are specified in the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. Once the MU has been properly authenticated and associated with the AP, the data transmission between the MU and the fixed backbone network can occur.
Data transmission between the various access points (APs) and their associated mobile units may involve large amounts of data which may take substantial amount of time and processing power to transmit over the air median. Such data transmissions are costly if the transmitted data is uncompressed. One possible solution to this problem is to always compress data prior to transmitting the data over the air. However, such an inflexible solution may not work under various circumstances because of the dynamic nature of data transmission in a wireless network due to various factors including the size and type of the data to be transmitted, the computational cost or overhead (in terms of time and processing power, etc.) in performing data compression at the sending end and data decompression at the receiving end, how much data waiting to be transmitted, and whether, for certain data streams, the benefit realized from compressing data outweighs the cost involved in performing data compression and decompression, etc. Thus, there is a need for the APs and the MUs to be able to transmit data in compressed format under appropriate conditions which will reduce the amount of time and processing power that it takes for data transmission in the wireless network.